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Smart software helps robots dodge collisions

By Duncan Graham-Rowe

A smart new software system has been developed that aims to make it impossible for robots to bump into objects, including people.

The Inevitable Collision System (ICS), developed by French and Japanese researchers, works by continuously calculating an exclusion zone around the robot based on its motion and that of the objects around it. The exclusion zone represents the region in which a collision would be unavoidable, no matter what evasive action the robot took.

Most existing mobile robots pose little danger to people, because they are so light and their motors are relatively feeble. But actuators and motors will inevitably become more powerful if robots are to become genuinely useful.

They are also increasingly being deployed in people’s homes, according to the World Robotics Survey, published in October by the United Nations Economic Commission for Europe. In 2002, the number of domestic and entertainment robots in use tripled and this trend is set to accelerate, says the report.

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ICS is a generic program, designed to be applied to a broad range of robotic applications, says Thierry Fraichard, at French national research institute, INRIA Rhône-Alpes, who presented his work at the Intelligent Robots and Systems conference in Las Vegas recently.

Bumper system

Collision avoidance systems for robots already exist. The simplest are passive “bumper” systems, which simply stop the robot when they sense a nearby object. But this strategy does not take into account any movement of the robot or objects, leaving the possibility of an unavoidable last-minute collision.

Other systems do take movement into account by calculating the future positions of all the objects. The problem is, Fraichard told New Scientist, that this can be an extremely complex problem if there are multiple objects or non-linear movements. “It is usually not possible to compute quickly a complete motion from the current state of your robot to its goal,” he says.

The solution, devised by Fraichard and Hajime Asama at the University of Tokyo, is to work out only partial trajectories of the robot and other objects. How far into the future the trajectories are projected is determined by the computing power available. The calculations are then continuously updated, meaning an exclusion zone can be determined in real-time.

Recorded roboticide

Blay Whitby, an artificial intelligence expert at the University of Sussex, UK, says not enough research has been done into making robots safer&colon; “The discipline ‘Safety-Critical Computing’ is barely 10 years old.”

He does not believe it is possible to make a robot completely safe. But he adds&colon; “Of course, no guarantee of safety does not mean that we should not try as hard as possible to be as safe as possible.”

To date there has only been one recorded roboticide. In 1981, Japanese factory worker Kenji Urada was killed by a robot in a manufacturing plant. Urada had climbed into the robot’s operating zone to fix something when he accidentally switched the robot back on. The hydraulic robot failed to sense Urada and crushed him as it carried on with its tasks.

The death led to a change in regulations and factory robots were fenced in to prevent similar accidents from occurring. But this is not possible for mobile robots.